A Study Of Gravitational Field And Periodic Orbit Near Irregular Asteroids

With the development of science and technology and the advancement of aerospace technology,human beings have begun to set their sights on the distant deep space.Whether it is the asteroid defense that worries the world or the asteroid detection that is curious about unknown science.It is indispensable to study the dynamic characteristics of asteroids.In this paper,the gravitational fields and periodic orbits near irregular asteroids are studied.For irregular asteroids,due to their complex shape,the gravitational field distribution around them is very irregular,and the closer the asteroid is to the surface,the more severe the gravitational changes.Proximity detection has important practical significance.At present,the common irregular gravitational field modeling methods have their advantages and disadvantages in terms of versatility,calculation speed,calculation accuracy,scope of application and additional storage capacity.In this paper,a more balanced rapid estimation method of gravitational acceleration that can take into account these indicators is proposed-PTK method,and the irregular asteroid 433 Eros is taken as an example to carry out numerical simulation of the above five indicators,and the simulation results show that The PTK method can achieve fast and accurate estimation of the gravitational acceleration near irregular asteroids with minimal storage cost on the basis of ensuring universality and globality.Periodic orbits near irregular asteroids are a new perspective to help us understand the dynamic characteristics of asteroids.The first thing to solve is how to quickly and comprehensively find periodic orbits near asteroids.In this paper,an innovative periodic orbit search strategy is proposed,that is,the initial value conjecture of the periodic orbit is obtained by randomizing a rough search in the parameter space,and then the genetic algorithm is used to perform a fine search in the interval near the initial value conjecture to find the initial value of the periodic orbit.Also taking the Eros asteroid as the object and based on the rapid estimation method of gravitational acceleration extended from the PTK method,several groups of periodic orbit types and spatial distribution rules near the asteroid 433 Eros were obtained by numerical simulation.The solar gravity and light pressure are introduced to analyze the changes of different orbits under the action of perturbation force.Stones from other mountains can attack jade.This paper takes the OSIRIS-REx mission as the research object,explores its scientific goals and mission planning,and reproduces the mission orbit,aiming to provide a certain reference for my country’s future small celestial body detection missions.The dynamic environment of the OSIRIS-REx spacecraft in two orbits of different heights near the asteroid Bennu is studied,the PTK method is combined with the actual engineering task,and the influence of different sampling models on the PTK method is explored.Through numerical simulation,the fast and accurate performance of the PTK method in spacecraft orbit prediction is demonstrated.